The present invention relates to a BGA (Ball Grid Array) type semiconductor device having area array type electrodes on an underside and a periphery thereof, and more particularly, to a socket for testing of semiconductor devices, suitable for testing of semiconductor devices having a fine pitch of 0.5 mm or less between electrodes, and a semiconductor device shipped after going through the testing process.
In recent years, ICs (for example, BGA) constructed to use projection electrodes, such as solder bumps or the like, for external connection electrodes have been presented in order to attempt miniaturization of IC packages. Further, to attempt further miniaturization of IC packages, it has been demanded for semiconductor devices having the above described projection electrodes to be made high in density and in speed. With such demand, there is a tendency that a pitch between projection electrodes has become further small.
Meanwhile, the characteristic test such as the burn-in test or the like is performed on ICs manufactured with respect to whether the ICs have a predetermined characteristics. At the time of testing, the ICs are tested in a state, in which they are mounted on a socket for testing of IC.
Accordingly, it is also necessary for the socket for testing of ICs to accommodate the tendency of ICs making high in density and minute. Also, projection electrodes themselves have decreased exceedingly in strength with the tendency of ICs making high in density and minute, so that it is necessary for projection electrodes not to be damaged even if contact pins provided on the socket for testing of ICs are brought into contact with them.
To meet the need for such sockets for testing of ICs, arcuate-shaped contact pins of metal supported by a floating member made of an organic material are used in, for example, the invention described in Japanese Patent Unexamined Publication No. 09-289068.
That is, the invention described in the above described Publication provides a construction, in which arcuate-shaped portions of the contact pins serve as a stopper for the floating member to control pushing amounts of the contact pins to inhibit deformation of solder balls even if terminals of the solder balls soften in a heat test or the like.
Also, in the invention described in Japanese Patent Unexamined Publication No. 10-69955, a substrate for testing, and solder bumps on an IC are connected to each other by a plurality of metallic contact pins, which are supported by an elastic member.
The invention described in the above described Publication provides a construction, in which deformation of the solder balls is inhibited by making a diameter of such plurality of metallic contact pins possible for the contact pins to pierce the solder balls, and favorable contact is obtained by electrically connecting the contact pins to the solder balls through piercing of the contact pin ends into the solder balls.
Because the socket for testing of ICs in the above described prior art premises the use of metallic contact pins, however, further minute contact pins must be formed in order to accommodate small pitches of external electrode attributable to the small sizing of IC packages, but such measures are limited in terms of cost and technique.
Further, with the construction of a socket for testing of ICs, in which contact pins are used, since it is difficult to mount the contact pins directly on a base substrate intended for testing when arrangement of the contact pins in small pitch is attempted, it is required that wiring be once laid on an intermediate substrate and pins for connection to the base substrate be formed.
In contrast, a socket construction for testing of ICs has been conceived and realization thereof has been under review, in which construction metallic contact pins are done away with and which comprises a tape circuit 2 with electrode pads corresponding to an external electrode arrangement of an IC, and an elastomer sheet 1 provided between the tape circuit 2 and a mother socket 4, as shown in FIG. 2.
A construction of a socket circuit for testing of ICs with the use of the above described tape circuit will be generally described with reference to FIG. 2. In the construction, the tape circuit 2 having electrode pads corresponding to an external electrode arrangement of an IC 5 is provided between an IC socket body 8 and the mother socket 4, and the elastomer sheet 1 is provided between the tape circuit 2 and the mother socket 4.
The IC 5 being tested is guided by the IC socket body 8 to be inserted thereinto, and external electrodes of the IC 5 are pushed against external electrodes formed on the tape circuit 2 for testing of the IC. A socket construction using the tape circuit 2 is effective as a socket construction for testing of fine pitch type ICs in that it is relatively easy to make electrode pads small in pitch and minute, and the construction is substantially inexpensive as compared with metallic contact pins, and parts except the tape circuit are made common in various applications.
Hereupon, with the above described socket construction using metallic contact pins, positions of the respective pins can displace independently in a vertical direction when pushed by external projection electrodes (for example, solder bumps) of an IC being tested, so that dispersion in height between adjacent external projection electrodes of the IC is easy to be accommodated.
In contrast, with the socket construction using a tape circuit, an elastomer sheet is disposed on a portion of the tape circuit, on which an IC is mounted (inserted), in order to prevent a surface of the tape circuit from continuously deforming when pushed by external projection electrodes of the IC being tested.
This is directed to accommodating such dispersion in height by causing local deformation of the elastomer sheet, which is produced by pushing of the external projection electrodes on the IC, to spread over a region of electrode pads on the tape circuit, which pads are not pushed by virtue of external projection electrodes being small in height.
However, because the elastomer sheet is small in rigidity as compared with the tape circuit, deformation of the elastomer sheet caused by pushing almost spreads in a out-of-plane direction, and a region, which is not pushed by external projection electrodes, is deformed under the influence of tension of the tape circuit, with the result that little effects are obtained in accommodating dispersion in height between adjacent external projection electrodes on an IC being tested, thus offering a problem involving a difficulty in executing accurate testing of semiconductor devices.
It is an object of the invention to realize a socket for testing of semiconductor devices, which is capable of accommodating dispersion in height between adjacent external projection electrodes on an IC and accurately testing semiconductor devices, which are made minute and high in density, a method of testing semiconductor devices, a method of manufacturing semiconductor devices with the use of the testing method, and semiconductor devices manufactured by the manufacturing method.
To attain the above described object, the invention is constituted as follows:
(1) A socket for testing of semiconductor chips having a plurality of external projection electrodes arranged on an underside and a periphery of a semiconductor chip body in an area array fashion, the socket comprising a tape circuit having electrode pads formed in an area array fashion, a mother socket supporting the tape circuit, and an elastomer sheet provided between the tape circuit and the mother socket, the elastomer sheet being formed on a surface thereof with grooves.
(2) A socket for testing of semiconductor chips having a plurality of external projection electrodes arranged on an underside and a periphery of a semiconductor chip body in an area array fashion, the socket comprising a tape circuit having electrode pads formed in an area array fashion, a mother socket supporting the tape circuit, and an elastomer sheet provided between the tape circuit and the mother socket, the elastomer sheet being formed on a surface thereof with cuts.
(3) Preferably, in the socket in (1) or (2), the surface of the elastomer sheet is divided in lattice, and intersections of respective lattice lines defining the lattice are disposed in an area to face positions of the electrode pads formed on the tape circuit.
(4) Preferably, in the socket in (1) or (2), the surface of the elastomer sheet is divided in lattice, and a spacing between the respective lattice lines defining the lattice is substantially the same as a spacing between the electrode pads formed on the tape circuit.
(5) Preferably, in the socket in (1), (2), (3), or
(4), that surface of the elastomer sheet, which faces the tape circuit, is divided in lattice.
(6) Preferably, in the socket (1), (2), (3), (4), or (5), the elastomer sheet is an insulating sheet having a hardness of 50xc2x0 H or more.
(7) A method of manufacturing semiconductor devices having a plurality of external projection electrodes on an underside of and a periphery of a semiconductor chip body in an area array fashion, the method comprising a burn-in testing step of using a socket for testing of semiconductor chips, which socket includes a tape circuit having electrode pads formed in an area array fashion, a mother socket supporting the tape circuit, and an elastomer sheet provided between the tape circuit and the mother socket and formed on a surface thereof with grooves, and performing testing by pushing the external projection electrodes of the semiconductor device against the electrode pads on the tape circuit.
(8) A semiconductor device having a plurality of external projection electrodes on an underside of and a periphery of a semiconductor chip body in an area array fashion, the semiconductor device being tested by a burn-in testing, in which a socket for testing of semiconductor chips, including a tape circuit having electrode pads formed in an area array fashion, a mother socket supporting the tape circuit, and an elastomer sheet provided between the tape circuit and the mother socket and formed on a surface thereof with grooves, is used and the external projection electrodes of the semiconductor device are pushed against the electrode pads on the tape circuit.
(9) A method of manufacturing semiconductor devices having a plurality of external projection electrodes on an underside of and a periphery of a semiconductor chip body in an area array fashion, the method comprising the steps of using a socket for testing of semiconductor chips, which socket includes a tape circuit having electrode pads formed in an area array fashion, a mother socket supporting the tape circuit, and an elastomer sheet provided between the tape circuit and the mother socket and formed on a surface thereof with grooves, and performing a burn-in testing by pushing the external projection electrodes of the semiconductor device against the electrode pads on the tape circuit.
(10) Preferably, in the semiconductor device in (8), a spacing between the plurality of external projection electrodes on the semiconductor device is 0.5 mm or less.
With the use of the above described measures, it is possible to provide a socket construction for testing of ICs, which is of tape circuit type and is excellent in the capacity of accommodating dispersion in height between adjacent external projection electrodes on an IC being tested.
Since the elastomer sheet is formed with grooves or cuts, respective divided portions defined by the grooves or cuts on the elastomer sheet are made independent from one another to be capable of accommodating pushing forces from solder bumps.
Accordingly, even if the solder bumps, respectively, are varied in height, the respective portions defined by the grooves or cuts are hardly affected by one another, and accommodate pushing forces exerted by the solder bumps, thus enabling providing sure contact between the solder bumps and the electrode pads.